No major photo-shopping. Minor editing such as exposure, contrast and such for small fixes is acceptable.

Capture date rules:

No restrictions.

Additional rules:

My ambiguity in the theme is intentional: I do not want to limit users to just one specific range of the spectrum, all I am proposing is that the main concept be somewhere in the vicinity of blue or cyan. This means, if it's getting too close to green or purple, that's out of the color range I am suggesting.